1. Field of the Invention
The present invention relates to interrupt control apparatuses and interrupt control methods, and is particularly suitable for use in an interrupt control apparatus that controls the output of multiple pieces of interrupt information (interrupt voice or interrupt images) in accordance with priority levels set for each of the pieces of interrupt information.
2. Related Art
The use of electronics in vehicles is increasing as of late, and on-vehicle information systems that use information technology (IT) to enhance vehicle safety, ensure more comfortable travel, and so on are increasingly being introduced. This type of on-vehicle information system often includes an on-vehicle device that provides voice information. A navigation device that uses voice information to provide route guidance to a destination, traffic information, or the like is an example of such an on-vehicle device. Meanwhile, there are also obstruction warning generation devices that use an on-vehicle camera or the like to detect obstructions in the vicinity of the vehicle and then use voice information to provide warning messages. Furthermore, it is likely that sensor warning sounds used for speed warnings, remaining gasoline warnings, or the like, which are at present outputted only as simple alarm sounds, will instead be provided as voice information such as warning messages through on-vehicle devices in the future.
Unlike radio, music, or the like, such voice information is not continuously outputted from the on-vehicle device; the voice information is instead an interrupt voice message outputted as necessary at a required timing. For example, when the vehicle approaches a point within a predetermined distance from an intersection that is part of a guidance route while music such as a CD (compact disk) is being played back, a voice message for guiding the direction of travel of the vehicle along the guidance route is provided as an interrupt voice message. In other words, the output of the music that is being played back is suspended, and the voice message for the route guidance is outputted as an interrupt.
If multiple interrupt voice messages for route guidance, an obstruction warning, a sensor warning, or the like are available, there are cases where different interrupt voice messages will occur as interrupts at the same time. In such a case, it is necessary to resolve these interrupt voice messages, and several techniques for such resolution have been proposed (for example, see JP2000-65585A, JP1998(H10)-104009A, and JP2010-79487A).
For example, with the technique disclosed in JP2000-65585A, priority levels are set for each of multiple interrupt voice messages. In the case where an interrupt voice message having a higher priority level occurs while another interrupt voice message is being outputted, the output of the current interrupt voice message is suspended, and the interrupt voice message with a higher priority level is preferentially outputted. The suspended interrupt voice message, which has a lower priority level, is then once again outputted from the beginning after the output of the high-priority level interrupt voice message ends.
Meanwhile, according to the technique disclosed in JP1998(H10)-104009A, the priority order of interrupt voice messages is made variable depending on circumstances. For example, JP1998(H10)-104009A discloses lowering the priority of information for which a long amount of time has passed since the information was included (paragraph 0113). JP1998(H10)-104009A also discloses raising the priority of navigation information and lowering the priority of other information (such as news information) when the vehicle has approached a point in a guidance route (paragraph 0115).
Furthermore, according to the technique disclosed in JP2010-79487A, in the case where new information has been received from a roadside device during the output of a voice message encouraging caution based on information previously received from a roadside device, the voice message encouraging caution based on the new information is outputted after the output of the current voice message has ended.
However, with the technique disclosed in JP2000-65585A, if an interrupt voice message having a higher priority level occurs as an interrupt during the output of another interrupt voice message, the output of that other interrupt voice message will be suspended. Suspending the output of the interrupt voice message is problematic in that it causes stress in a user who is listening to the interrupt voice messages.
Furthermore, with the technique disclosed in JP2000-65585A, the suspended interrupt voice message is once again outputted from the beginning, after the output of the higher-priority level interrupt voice message ends. There is thus a problem in that the user is forced to listen to a voice message he or she has already listened to all over again from the beginning, which causes stress in the user. In particular, in the case where the output of a voice message is suspended near the end of that voice message, the user is forced to listen to almost the entire voice message again, which causes a large amount of stress in the user.
As opposed to this, according to the technique disclosed in JP1998(H10)-104009A, the priority of navigation information is raised and the priority of news information is lowered when the vehicle is approaching a point in a guidance route. Therefore, the navigation information is given priority over the news information, and the navigation information is outputted. However, even if the vehicle is at a point in the guidance route, the output of the navigation information also will be suspended if an interrupt voice message that has a higher priority than the navigation information occurs as an interrupt. The aforementioned problem can therefore also occur in the technique according to JP1998(H10)-104009A.
According to the technique disclosed in JP2010-79487A, the output of a voice message currently being carried out is given the highest priority. Accordingly, a voice message that is currently being outputted will not be suspended even if a new voice message occurs as an interrupt during the output of the current voice message. However, with JP2010-79487A, the new voice message will not be immediately outputted as an interrupt during the output of the current voice message, regardless of how high a priority level the new voice message has. There is thus a problem in that interrupt voice messages having a high level of urgency, such as messages warning of obstructions, will not be immediately outputted, which interferes with the appropriate output timing.